What is the question though?
Answer:
La investigación social permite nuevos conocimientos o estudia una situación social para diagnosticar necesidades y problemas con el propósito de aplicar los conocimientos con fines prácticos de todos los tiempos (investigación aplicada).
Explanation:
Demographic Transition
Population aging is a by-product of the process known as "<em>Demographic Transitioning</em>." This process is determined mostly by fertility and mortality rate. For example: a population that has a high fertility rate has a low amount of older people, and vise versa.